Re: [patch] (but not for gnulib) squash git diff spurious exit code 1

[Thien-Thi Nguyen]

below is an updated patch.  it skips all output,
instead of just the stats, for this special case.

thi

_____________________________________________________________________
 * diff.c (CHANGE_MIND_LAST_MOMENT_MAYBE): New macro.
 (show_stats): Use it immediately prior to output.
 (show_shortstats): Likewise.  Also, take 2nd arg OPTIONS.
 (diff_flush): Update calls to `show_stats' and `show_shortstats'.
 Also, if we changed our mind, skip all further output.


--- diff.c.ORIG 2007-10-31 21:04:37.000000000 +0100
+++ diff.c      2007-12-27 23:27:52.000000000 +0100
@@ -823,6 +823,16 @@
        printf("%s", reset);
 }
 
+/* If due to these supposedly output-only (sneer) wranglings
+   we have determined there are actually no changes, backpatch
+   the overall status and avoid any output.  Blech.  --ttn  */
+#define CHANGE_MIND_LAST_MOMENT_MAYBE() do {   \
+    if (! total_files) {                       \
+      options->has_changes = 0;                        \
+      return;                                  \
+    }                                          \
+  } while (0)                                  \
+
 static void show_stats(struct diffstat_t* data, struct diff_options *options)
 {
        int i, len, add, del, total, adds = 0, dels = 0;
@@ -957,11 +967,12 @@
                free(data->files[i]);
        }
        free(data->files);
+       CHANGE_MIND_LAST_MOMENT_MAYBE ();
        printf("%s %d files changed, %d insertions(+), %d deletions(-)%s\n",
               set, total_files, adds, dels, reset);
 }
 
-static void show_shortstats(struct diffstat_t* data)
+static void show_shortstats(struct diffstat_t* data, struct diff_options 
*options)
 {
        int i, adds = 0, dels = 0, total_files = data->nr;
 
@@ -985,7 +996,7 @@
                free(data->files[i]);
        }
        free(data->files);
-
+       CHANGE_MIND_LAST_MOMENT_MAYBE ();
        printf(" %d files changed, %d insertions(+), %d deletions(-)\n",
               total_files, adds, dels);
 }
@@ -3055,7 +3066,10 @@
                if (output_format & DIFF_FORMAT_DIFFSTAT)
                        show_stats(&diffstat, options);
                else if (output_format & DIFF_FORMAT_SHORTSTAT)
-                       show_shortstats(&diffstat);
+                       show_shortstats(&diffstat, options);
+               /* If we changed our minds, avoid further output totally.  */
+               if (! options->has_changes)
+                       goto free_filepairs;
                separator++;
        }
 
@@ -3085,6 +3099,7 @@
        if (output_format & DIFF_FORMAT_CALLBACK)
                options->format_callback(q, options, 
options->format_callback_data);
 
+free_filepairs:
        for (i = 0; i < q->nr; i++)
                diff_free_filepair(q->queue[i]);
 free_queue: